<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>getElementsByTagName获取checkbox进行全选</title>
		<style type="text/css">
			#myTable{ width: 900px; margin: 0px auto; background-color: #008000;}
			#myTable td,#myTable th{ background-color: white;}
			#myDiv{width: 900px; margin: 0px auto; height: 30px; line-height: 30px; 
			text-align: center;}
		</style>
		<!-- <script>======代码======</script> -->
	</head>
	<body >
		<table cellspacing="1" id="myTable">
			<tr>
				<th width="100">
                  <input type="checkbox" id="selAll" onchange="" />全选
				<input type="checkbox" id="selAll2" onchange=""  />反选
                        </th>
				<th width="100">姓名</th>
				<th width="100">性别</th>
				<th width="100">专业</t 	 	h>
				<th width="100">爱好</th>
			</tr>
			<tr>
				<td><input type="checkbox" class="T"/></td>
				<td>刘备</td>
				<td>男</td>
				<td>软件开发</td>
				<td>抽烟</td>
			</tr>
			<tr>
				<td><input type="checkbox" class="T"/></td>
				<td>关羽</td>
				<td>男</td>
				<td>国际贸易</td>
				<td>喝酒</td>
			</tr>
			<tr>
				<td><input type="checkbox" class="T"/></td>
				<td>张飞</td>
				<td>男</td>
				<td>园林设计</td>
				<td>烫头发</td>
			</tr>
			<tr>
				<td><input type="checkbox" class="T"/></td>
				<td>赵云</td>
				<td>男</td>
				<td>平面设计</td>
				<td>抽烟</td>
			</tr>
			<tr>
				<td><input type="checkbox" class="T"/></td>
				<td>黄忠</td>
				<td>男</td>
				<td>影视制作</td>
				<td>玩游戏</td>
			</tr>
			<tr>
				<td><input type="checkbox" class="T"/></td>
				<td>小乔</td>
				<td>女</td>
				<td>高级护理</td>
				<td>唱歌</td>
			</tr>
		</table>
		<script>
			var ckAll = document.getElementById("selAll");
			var cks = document.querySelectorAll("#myTable .T");
			ckAll.onclick = function(){
				for (var i = 0; i < cks.length; i++) {
					cks[i].checked = this.checked;
				}
			txt.innerText = this.checked ? "全不选" : "全选";
			};
			for (var i = 0; i < cks.length; i++) {
				cks[i].onclick = fn;
			}

				ckAll.checked = flag;
				txt.innerText = flag ? "全不选" : "全选";
			}
		</script>
	</body>
</html>